A Space Vector Pulse Width Modulation (SVPWM) is a novel pulse width modulation for a three-level photovoltaic inverter. The SVPWM has many advantages, such as an improved harmonic spectrum of an output waveform and an increased utilization ratio of a direct current bus voltage, and thus is widely adopted.
However, the three-level photovoltaic inverter in the SVPWM mode is easy to have faults or abnormal problems (such as a midpoint potential offset or an excessively large common mode leakage current formed when a ground stray capacitance of a photovoltaic assembly is large), thereby affecting safety and stability of operation of a grid-connected photovoltaic system.